As the production from oil and gas fields is depleted, it is desirable to use some of the wells and their associated valving and piping for water injection as part of a secondary recovery program. Typical installations have the gathering lines or piping and choke valves initially installed in a permanent manner with the choke valves oriented for production from the oil or gas well. If the decision is subsequently made to use a particular well for water injection, and flow in the reverse direction through a particular choke valve is required, previous designs have necessitated that the choke valve be unbolted or the pipe line be cut. This is due to previous choke valves having been designed for flow in one direction. Reinsatallation then entails rerouting of lines and welding to allow the new choke valve to be properly oriented for reverse flow. This removel, rerouting and reinstallation involves considerable time and expense for the field operator.
This invention is for an improved cartridge chocke valve which is pressure balanced to reduce the loads imposed on the actuation means. It uses a cage style trim to provide the superior flow control characteristics and wear resistance typical of the cage design. A removable cartridge assembly allows the body to remain in the flowline during reversal of the trim thereby permitting flow in either direction. Prior valves with reversible trim include the valve disclosed in the E. A. Corbin, Jr. U.S. Pat. No. 2,196,202. The Corbin valve allows reversal of its internal trim but requires an actuator which can work in either direciton.
The W.S.M.E. Crake U.S. Pat. No. 2,296,534 discloses a flow control valve with cage style trim in which a plurality of holes of varying diameter arranged in a helical manner are used to allow a more accurate cotnrol of the flow rate. A pressure balanced cage is disclosed with an outlet port disposed at a right angle thereto.
The G. A. Keith U.S. Pat. No. 3,606,911 discloses another valve with reversible trim to allow changing the flow characteristics of the valve. The Keith invention does not provide for pressure balancing of the cage.
The M. R. Jones U.S. Pat. No. 3,589,674 discloses a ball valve with internal trim that can be easily replaced as a complete unit. The Jones structure is not pressure balanced and does not permit throttling of the flow.